I am new to cool weather crops.

I planted Cauliflower, Cabbage, and Kohlrabi about 3 weeks ago. The leaves look stressed. Some are yellowing and browning. Others look pest-eaten (the same way my hostas have looked after slug damage).

In the past I think I have tended to overwater my warm weather vegetables so I am keeping in tune with soil moisture and watering as needed (it's still 40s-50s here in Seattle).

Are there typical pests or maintenance problems I need to be aware of for these cool weather vegetables?

Thanks!